Northern lights are not commonly seen at Yellowstone. According to rangers at the park, it's a rarity that occurs only on a very clear night and, at best, will be quite faint. One ranger I spoke with has lived in Yellowstone for ten years and only seen them once or twice. Thus, I'd have to place your odds pretty low. Better bet to see them would be at the national parks of Alaska!

Have a nice trip to Yellowstone and be sure to come back to OhRanger.com to share your experience, especially if you happen to have a once in a decade sighting!